I personally like clean icons like the Fugue set (www.pinvoke.com) or the Silk icon set (www.famfamfam.com). But neither of these designers is available for freelancing projects!
I can also recommend Emanuel Sa (http://www.emanuelsa.com/) - He's WAY cheaper and just as good.
Also I'd say David Lanham (http://dlanham.com/) & Fernando Lins (http://www.devixdesign.com/) are among the best as well.
I am however compelled to say that at the price of 1000 USD per icon, you actually come out to a 1.5 cents per pixel of a 256x256 icon, or about 65 pixels per dollar.
Now that doesn't sound as bad as the million dollar homepage, is much better looking than that brain-fart of an idea, and it's "yours." You get a custom icon for your application, and damn it looks good.
Mantia's homepage shows that he can pretty much consistently do an icon of that quality in one day.
Here comes the second part of the calculation... as a consultant/expert doing enterprise integration (and I'm talking enterprise - multinational telcos, airports) in Europe I can expect to earn about 400€ per day. That's about 535 USD per day.
I realize Mantia is earning about twice as much as I can per day and I get confused. It's not even only about the money: while I am considered nothing more than a higher-up keyboard jockey, he gets the kudos for being an artist.
To the proponents of the theory that programming is actually an art: have I chosen to live off of a wrong art type? :-p
He through these people for O2 right now - http://www.thbs.com/
No seriously, I don't know Mantia, but maybe he is famous or really especially good. It is maybe harder to become famous as a programmer, but on the other hand it is easier to make an acceptable income as an unknown programmer. But think about it, would Linus Torvalds, or dhh, or Rod Johnson (of spring framework) or some other famous developers work for 400€/day? I highly doubt it.
So just market yourself better, and hit those 1000€/day.
Oh, also another consideration: if you are consulting for telcos or whatever, you are typically hired for months, earning 400€ each day. The same telco might just commission 10 icons to Mantia, equaling 10 days of work.
When you care enough about your new startup looking as good as it can be, a few thousand to have new icons made to make your site more usable and unique or your app more visible is worth the effort--or in this case, the capital.
A good designer is well worth his price. it's just a shame there is an overabundance of bad designers; they're each worth nothing more than 5 headaches, a poor end product, and a delayed project. But hey, you saved $500 in the process.
In programming there is an intended result, and for all intents and purposes, it doesn't matter how you get there. It's a 1 or 0 proposition.
Design on the other hand is full of subjective opinions from the client and even the designer that get in the way of defining what the intended result is. Worse, the only way to get close to that definition is to explore lots of different designs.
The process may look something like this:
1. client wants logo, gives the idea of spaceship 2. designer sketches 3 spaceships 3. client says he wanted the shuttle discovery 4. designer sketches up the space shuttle discovery 5. client says he wanted the moon in the background 6. designer adds the moon to the background 7. client signs off on sketch 8. designer renders sketch 9. client says saturn would be much better than the moon 10. designer changes moon to saturn 11. client says he thought space shouldn't be blue-black, it should be black. 12. designer makes space black 13. client says they've rethought the whole concept and need a daisy instead of the space shuttle.
And that would be an easy client. If you start before step one, and the client says "I'll know it when I see it." you can go ahead and double or tripple your workload.
They get paid $1000+, up-front whether the app makes money or not, for something that has no bearing on the app's functionality. Genius.
For my app:
http://www.icons-icons.com/roma-icons.php <-- looks like Fisher-Price with big, bold, colorful icons. A perfect fit for my target users, and I managed to snaggle them on sale for $25.
For my website:
I originally made my own buttons. They worked, and I gradually iterated them upwards, but I'm ultimately not a designer. When I got the site redone I had both my web designer make some concepts and paid for a dedicated designer to make some concepts and, importantly, give me the components (to allow more mix-and-match fun as I tested which converted best).
My web gal: http://www.gursimran.com My icon/logo designer: http://www.logosamurai.com/
Looks like they're having web site trouble at the moment. Ahh well, this is why I use freelancers -- if your main provider goes dark, you switch. (I would have to look up the numbers but I think I got everything done for less than $300 in total, which is a pittance next to how much I make on the conversion lift.)
She recently took down her icon site, but still does icon work for people. Her freelance portfolio is here: http://www.kellishaver.com/
He works at iconfactory (http://iconfactory.com), and their icons in general are really delicious, although probably not cheap.